Circuit device and manufacturing method of circuit device

ABSTRACT

After a trench  54  is formed in a conductive foil  60,  the circuit elements are mounted, and the insulating resin is applied on the conductive foil  60  as the support substrate. After being inverted, the conductive foil  60  is polished on the insulating resin  50  as the support substrate for separation into the conductive paths. Accordingly, it is possible to fabricate the circuit device in which the conductive paths  51  and the circuit elements  52  are supported by the insulating resin  50,  without the use of the support substrate. And the interconnects L 1  to L 3  requisite for the circuit are formed, and can be prevented from slipping because of the curved structure  59  and a visor  58.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a circuit device and a methodfor manufacturing the circuit device, and more particularly to athin-type circuit device and a method of manufacturing the thin-typecircuit device without the need of providing a support substrate.

[0003] 2. Description of the Related Art

[0004] Conventionally, it has been demanded that a circuit device whichis set in an electronic apparatus is reduced in size, thickness andweight, because the circuit device is used for a portable telephone, aportable computer and so on.

[0005] For example, a semiconductor device as a circuit device istypically a package type semiconductor device which is conventionallysealed by normal transfer molding. This semiconductor device 1 ismounted on a printed circuit board PS as shown in FIG. 24.

[0006] This package type semiconductor device 1 has a semiconductor chip2 covered with a resin layer 3, with a lead terminal 4 for externalconnection derived from the side of this resin layer 3.

[0007] However, this package type semiconductor device 1 had the leadterminal 4 out of the resin layer 3, and was too large in total size tomeet smaller, thinner and lighter requirements.

[0008] Therefore, various companies have competed to develop a widevariety of structures which are reduced in size, thickness and weight.Recently, a wafer scale CSP which is as large as a chip size, called aCSP (Chip Size Package), or a CSP which is slightly larger than the chipsize, has been developed.

[0009]FIG. 25 shows a CSP 6 which adopts a glass epoxy substrate 5 as asupport substrate and which is slightly larger than a chip size. Herein,a transistor chip T is mounted on the glass epoxy substrate 5.

[0010] On the surface of this glass epoxy substrate 5, a first electrode7, a second electrode 8 and a die pad 9 are formed, and on the backface, a first back electrode 10 and a second back electrode 11 areformed. Via a through hole TH, the first electrode 7 and the first backelectrode 10, as well as the second electrode 8 and the second backelectrode 11, are electrically connected. On the die pad 9, the baretransistor chip T is fixed. An emitter electrode of transistor and thefirst electrode 7 are connected via a bonding wire 12, and a baseelectrode of transistor and the second electrode 8 are connected via thebonding wire 12. Further, a resin layer 13 is provided on the glassepoxy substrate 5 to cover the transistor chip T.

[0011] The CSP 6 adopts the glass epoxy substrate 5, which has themerits of a simpler structure extending from the chip T to the backelectrodes 10, 11 for external connection, and a less expensive cost ofmanufacture, than the wafer scale CSP.

[0012] The CSP 6 is mounted on the printed circuit board PS, as shown inFIG. 24. The printed circuit board PS is provided with the electrodesand wires making up an electric circuit, and has the CSP 6, the packagetype semiconductor device 1, a chip resistor CR and a chip capacitor CCfixed for the electrical connection.

[0013] A circuit on this printed circuit board is packaged in varioussets.

[0014] Referring to FIGS. 26 and 27, a method for manufacturing this CSPwill be described below. In FIG. 27, reference is made to a flow diagramentitled as a Glass epoxy/flexible substrate, listed in the middle.

[0015] Firstly, the glass epoxy substrate 5 is prepared as a basematerial (support substrate). On both sides of the glass epoxy substrate5, the Cu foils 20, 21 are applied via an insulating adhesive (see FIG.26A).

[0016] Subsequently, the Cu foils 20, 21 corresponding to the firstelectrode 7, the second electrode 8, the die pad 9, the first backelectrode 10 and the second back electrode 11 are coated with an etchingresist 22 and patterned. Note that the patterning may be made separatelyon the front face and the back face (see FIG. 26B).

[0017] Then, using a drill or a laser, a bore for the through hole TH isopened in the glass epoxy substrate. This bore is plated to form thethrough hole TH. Via this through hole TH, the electrical connectionbetween the first electrode 7 and the first back electrode 10 andbetween the second electrode 8 and the second back electrode 10 is made(see FIG. 26C).

[0018] Further, though being not shown in the figure, the firstelectrode 7 and the second electrode 8 which become the bonding postsare subjected to Ni plating or Au plating, and the die pad 9 whichbecomes a die bonding post is subjected to Au plating to effect diebonding of the transistor chip T.

[0019] Lastly, the emitter electrode of the transistor chip T and thefirst electrode 7, and the base electrode of the transistor chip T andthe second electrode 8 are connected via the bonding wire 12, andcovered with the resin layer 13 (see FIG. 26D).

[0020] As required, individual electrical elements are formed by dicing.In FIG. 26, only one transistor chip T is provided on the glass epoxysubstrate 5, but in practice, a matrix of transistor chips T areprovided. Accordingly, a dicing apparatus separates them into individualelements.

[0021] In accordance with the above manufacturing method, a CSP typeelectrical element using the support substrate 5 can be completed. Thismanufacturing method is also effected with the use of a flexible sheetas the support substrate.

[0022] On the other hand, a manufacturing method adopting a ceramicsubstrate is shown in a flow diagram to the left in FIG. 27. After theceramic substrate which is the support substrate is prepared, thethrough holes are formed. Then using a conductive paste, the electrodesare printed and sintered on the front face and the back face.Thereafter, the same manufacturing method of FIG. 26, up to coating theresin layer is followed, but since the ceramic substrate is veryfragile, and is likely to break off, unlike a flexible sheet or theglass epoxy substrate, there is a problem with the difficulty of moldingusing die. Therefore, a sealing resin is potted and cured, then polishedfor the uniform treatment of the face of the sealing resin. Lastly,using the dicing apparatus, individual devices are made.

[0023] In FIG. 25, the transistor chip T, connecting means 7 to 12, andthe resin layer 13 are requisite components for the electricalconnection with the outside, and the protection of transistor. However,only these components were difficult to provide an electrical circuitdevice reduced in size, thickness and weight.

[0024] Essentially, there is no need of having the glass epoxy substrate5 which becomes the support substrate, as described before. However,since the manufacturing method involves pasting the electrode on thesubstrate, the support substrate is required, and this glass epoxysubstrate 5 could not be dispensed with.

[0025] Accordingly, the use of this glass epoxy substrate 5 raised thecost. Further, since the glass epoxy substrate 5 was thick, the circuitdevice was thick, limiting the possibility to reduce the size, thicknessand weight of the device.

[0026] Further, the glass epoxy substrate or the ceramic substratenecessarily requires a through hole forming process for connecting theelectrodes on both sides. Hence, there was a problem with the longmanufacturing process.

[0027]FIG. 28 shows a pattern diagram on the glass epoxy substrate, theceramic substrate or a metal substrate. On this pattern, an IC circuitis typically made, with a transistor chip 21, an IC chip 22, a chipcapacitor 23 and/or a chip resistor 24 mounted. Around this transistorchip 21 or the IC chip 22, a bonding pad 26 integral with a wire 25 isformed to electrically connect the chips 21, 22 via a bonding wire 28. Awire 29 is made integrally with an external lead pad 30. These wires 25,29 are bent through the substrate, and made slender in the IC circuit,as necessary. Accordingly, this slender wire has smaller contact areawith the substrate, leading to exfoliation or curvature of the wire. Thebonding pad 26 is classified into a bonding pad for power and a bondingpad for small signal. Particularly, the bonding pad for small signal hasa small bonding area, which caused a film exfoliation.

[0028] Further, an external lead is fixed to an external lead pad 30.There was a problem that the external lead pad 30 might be exfoliateddue to an external force applied to the external lead.

SUNMMARY OF THE INVENTION

[0029] The present invention intends to obtain a semiconductor devicewhich is easy to be manufactured, and has a high accuracy andreliability.

[0030] The present invention has been achieved in the light of theabove-mentioned problems, and its object is to provide a circuit device,comprising:

[0031] a plurality of conductive paths;

[0032] a circuit element mounted on said desired conductive paths; and

[0033] a package of an insulating resin for coating said circuit elementand supporting integrally said conductive paths;

[0034] a plurality of lead terminals for connecting with outer circuit,the lead terminals being exposed from one surface of the package

[0035] Preferably, the conductive paths are made of pressed metal.

[0036] In the present invention, since a plate like body is used as aconductive plate for forming conductive path pattern and an isolationtrench is formed by half punching or half etching to form conductivepaths, conductive paths whose sheet resistance is very low, whosepattern is fine and whose surface is very flat, can be obtained.

[0037] Therefore, bonding reliability is very high and in the case ofmounting a high-integrated semiconductor circuit, high accuracy andreliability in the high-integrated semiconductor circuit device can berealized.

[0038] According to using a pressed metal as a conductive plate,boundaries are positioned at random, thereby sheet resistance is low andfine and very flat conductive paths in microscopic views can beobtained.

[0039] In the case that plating film whose thickness is formed so thickas to be able to use as conductive paths, film thickness is deviated anda sufficient flatness cannot be obtained. For example, when a platingfilm whose thickness is 20-100 μm is formed, it is difficult to have anuniform thickness of the plating film. Therefore bonding strength islowered.

[0040] Contrary that, in the case if conductive paths formed by halfetching a pressed metal such as copper foil, the surface of theconductive paths is very flat and bonding accuracy and bondingreliability are very high.

[0041] In the plating film, according to using a mirror polished surfaceof a substrate as a growth starting face of plating, then removing thesubstrate and using the growth starting face as a bonding face, flatnessof the bonding surface is slightly improved. However accuracy in thecase is inferior to use the pressed metal such as cooper.

[0042] Further according to the above structure, the present inventionhas following advantages. The semiconductor device of the presentinvention can be enduring a stress caused by a warp of a thin typepackage. Further an electrical connecting portion can be prevented frombeing polluted. Since rigidity is improved, operation efficiency can beimproved.

[0043] For example, by using a pressed metal including a Fe—Ni alloy asa main component, as the conductive path, thermal expansion coefficientcan be prevented from mis-matching, since thermal expansion coefficientof the silicon chip is near to that of the Fe—Ni alloy.

[0044] Further, by using a pressed metal including Al as a maincomponent, the device becomes lighter than that using a pressed metalincluding Cu or Fe—Ni as a main component. In this case, without forminga plating film, direct bonding can be conducted with using an Al wiringor Au wiring.

[0045] Since the conductive path is made of a material whose crystalboundary is disposed at random so that a surface of the conductive pathis flat, endurance against bending or rigidity can be improved and adeterioration of the conductive path.

[0046] Further a surface on which circuit element is to be formed iscovered with a conductive film made of metal material different from amaterial of the conductive path. Therefore warp or wire breaks of theconductive path caused by a stress, and reliability of connectingportion between a die-bonding portion and an element. Further accordingto using the conductive film made of Ni plating film, wire bonding usingAl wire can be conducted and formation of a visor (projected portion)can be formed.

[0047] Further, for example, the present invention has been achieved inthe light of the above-mentioned problems, and its object is to providea circuit device, comprising:

[0048] a plurality of conductive paths which are electrically isolated;

[0049] a plurality of circuit elements fixed on said desired conductivepaths; and

[0050] an insulating resin for coating said circuit elements andsupporting integrally said conductive paths;

[0051] wherein at least one of the plurality of said conductive paths isused for an interconnect to electrically connect the plurality of saidcircuit elements, and has a curved lateral face (side surface) to befitted with said insulating resin. The present invention can resolve theabove conventional problems with the minimum number of components, theconductive path being prevented from slipping off the insulating resin.

[0052] According to a second aspect of the invention, there is provideda circuit device, comprising:

[0053] a plurality of conductive paths which are electrically isolatedby a trench;

[0054] a plurality of circuit elements fixed on said desired conductivepaths; and

[0055] an insulating resin for coating said circuit elements andsupporting integrally said conductive paths by being filled into saidtrench between said conductive paths;

[0056] wherein at least one of the plurality of said conductive paths isused for an interconnect to electrically connect the plurality of saidcircuit elements, and has a curved lateral face to be fitted with saidinsulating resin. The present invention can resolve the aboveconventional problems in such a way that the insulating resin filledinto the trench supports the conductive path integrally to preventslippage of the conductive path.

[0057] According to a third aspect of the invention, there is provided acircuit device, comprising:

[0058] a plurality of conductive paths which are electrically isolatedby a trench;

[0059] a plurality of circuit elements fixed on said desired conductivepaths; and

[0060] an insulating resin for coating said circuit elements andsupporting integrally said conductive paths by being filled into saidtrench between said conductive paths, with the back face of saidconductive paths exposed;

[0061] wherein at least one of the plurality of said conductive paths isused for an interconnect to electrically connect the plurality of saidcircuit elements, and has a curved lateral face to be fitted with saidinsulating resin. The present invention can resolve the aboveconventional problems in such a way that the back face of conductivepath is utilized as an electrode for external connection, to preventslippage of the conductive path, while the through hole can be alsodispensed with.

[0062] According to a fourth aspect of the invention, there is provideda manufacturing method for a circuit device comprising the steps of:

[0063] forming the conductive paths having a curved lateral face bypreparing a conductive foil, and forming a trench having a smaller depththan the thickness of said conductive foil on said conductive foilexcluding at least a region which becomes a conductive path;

[0064] fixing a plurality of circuit elements on said desired conductivepaths;

[0065] coating and molding said circuit elements with an insulatingresin to be filled into said trench for fitting said conductive pathswith said insulating resin; and

[0066] forming a circuit by removing said conductive foil at a portionof thickness where said trench is not provided, to enable aninterconnect formed of a part of said conductive path to be electricallyconnected with said plurality of circuit elements. The present inventioncan resolve the above conventional problems in such a way that theconductive foil for forming the conductive paths is a starting material,and the conductive foil has a supporting function till the insulatingresin is molded, and the insulating resin has the supporting functionafter molding. There is no need of providing the support substrate.

[0067] According to a fifth aspect of the invention, there is provided amanufacturing method for a circuit device comprising the steps of:

[0068] forming the conductive paths having a curved lateral face bypreparing a conductive foil, and forming a trench having a smaller depththan the thickness of said conductive foil on said conductive foilexcluding at least a region which becomes a conductive path;

[0069] fixing a plurality of circuit elements on said desired conductivepaths;

[0070] providing connecting means for electrically connecting anelectrode of said circuit element with desired one of said conductivepaths;

[0071] coating and molding said circuit elements with an insulatingresin to be filled into said trench for fitting said conductive pathswith said insulating resin;

[0072] forming a circuit by removing uniformly said conductive foil at aportion of thickness where said trench is not provided from the backside and making the back face of said conductive paths and saidinsulating resin across said trench a substantially flat surface, toenable an interconnect formed of a part of said conductive path to beelectrically connected with said plurality of circuit elements. Thepresent invention can resolve the above conventional problems in such away as to have bonding which is prevented from slipping and form a flatcircuit device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] [FIG. 1]

[0074]FIG. 1 is a view for explaining a circuit device according to thepresent invention.

[0075] [FIG. 2]

[0076]FIG. 2 is a view for explaining the circuit device of theinvention.

[0077] [FIG. 3]

[0078]FIG. 3 is a view for explaining a method for manufacturing thecircuit device of the invention.

[0079] [FIG. 4]

[0080]FIG. 4 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0081] [FIG. 5]

[0082]FIG. 5 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0083] [FIG. 6]

[0084]FIG. 6 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0085] [FIG. 7]

[0086]FIG. 7 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0087] [FIG. 8]

[0088]FIG. 8 is a view for explaining the circuit device of theinvention.

[0089] [FIG. 9]

[0090]FIG. 9 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0091] [FIG. 10]

[0092]FIG. 10 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0093] [FIG. 11]

[0094]FIG. 11 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0095] [FIG. 12]

[0096]FIG. 12 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0097] [FIG. 13]

[0098]FIG. 13 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0099] [FIG. 14]

[0100]FIG. 14 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0101] [FIG. 15]

[0102]FIG. 15 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0103] [FIG. 16]

[0104]FIG. 16 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0105] [FIG. 17]

[0106]FIG. 17 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0107] [FIG. 18]

[0108]FIG. 18 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0109] [FIG. 19]

[0110]FIG. 19 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0111] [FIG. 20]

[0112]FIG. 20 is a view for explaining the method for manufacturing thecircuit device of the invention.

[0113] [FIG. 21]

[0114]FIG. 21 is a view for explaining a circuit device of theinvention.

[0115] [FIG. 22]

[0116]FIG. 22 is a view for explaining a circuit device of theinvention.

[0117] [FIG. 23]

[0118]FIG. 23 is a view for explaining a way of mounting the circuitdevice of the invention.

[0119] [FIG. 24]

[0120]FIG. 24 is a view for explaining a mounting structure of theconventional circuit device.

[0121] [FIG. 25]

[0122]FIG. 25 is a view for explaining the conventional circuit device.

[0123] [FIG. 26]

[0124]FIG. 26 is a view for explaining a method for manufacturing theconventional circuit device.

[0125] [FIG. 27]

[0126]FIG. 27 is a view for explaining the method for manufacturing theconventional circuit device and the circuit device of the presentinvention.

[0127] [FIG. 28]

[0128]FIG. 28 is a pattern diagram of an IC circuit which is applicableto the conventional circuit device and the circuit device of theinvention.

[0129] [FIG. 29]

[0130]FIG. 29 is a diagram for explaining the relation between thesemiconductor manufacturer and the set maker.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0131] First Embodiment for Circuit Device

[0132] Referring to FIG. 1, a circuit device of the present inventionwill be first described below in connection with its structure.

[0133]FIG. 1 shows a circuit device 53 in which a conductive path 51 isburied into an insulating resin 50, and a circuit device 52 is fixed onsaid conductive path 51 supported by the insulating resin 50. Thelateral face of the conductive path 51 has a curved structure 59.

[0134] This circuit device is mainly composed of the circuit elements52A, 52B, a plurality of conductive paths 51A, 51B and 51C, and theinsulating resin 50 into which the conductive paths 51A, 51B and 51C areburied. Between the conductive paths 51, a trench 54 is filled with theinsulating resin 50. And the insulating resin 50 supports the conductivepaths 51 of the curved structure 59.

[0135] The insulating resin may be a thermosetting resin, such as epoxyresin, or a thermoplastic resin, such as polyimide resin andpolyphenylene sulfide. Also, the insulating resin may be any of theresins as far as they can be set by the use of a molding die, or coatedby dipping or application (coating) Further resin including fiber calledas Pre-preg is also applicable. The conductive path 51 may be aconductive foil composed of Cu as the main substance, a conductive foilcomposed of Al as the main constituent, or a conductive foil composed ofan alloy of Fe—Ni. Other electrically conductive materials may be ofcourse usable. A conductive material which can be etched or evaporate bylaser is preferable.

[0136] In the present invention, the dry etching or wet etching is usedfor the non-anisotropic (isotropic) etching to have the lateral face ofthe conductive path 51 curved, bringing about the anchor effect.

[0137] Therefore, the conductive path 51 is prevented from slipping offthe insulating resin 50.

[0138] Connecting means for the circuit elements 52 may be a bondingwire 55A, a conductive ball made of brazing material, an oblateconductive ball, a brazing material 55B such as solder, a conductivepaste 55C such as Ag paste, a conductive coat, or an anisotropicconductive resin. These connecting means may be selected depending onthe kind of the circuit element 52, and the mounting mode of the circuitelement 52. For example, for the bare semiconductor element, a bondingwire is selected to connect the electrode on the surface of theelectrode and the conductive path 51. For the CSP, a solder ball orsolder bump is selected. For the chip resistor or chip capacitor, thesolder 55B is selected. The circuit element packaged, for example, aBGA, can be mounted in the conductive path 51 without causing anyproblem, in which the connecting means may be solder.

[0139] To fix the circuit element 52A with the conductive path 51A, aninsulating adhesive is selected if the electrical connection isunnecessary. If the electrical connection is required, the conductivecoat is adopted. Herein, at least one layer of conductive coat may berequired.

[0140] The conductive coat materials may be Ag, Au, Pt or Pd, which iscoated by evaporation, sputtering or CVD under low vacuum or highvacuum, plating, or sintering.

[0141] For example, Ag is adherent to Au, as well as the brazingmaterial. Hence, if an Au coat is applied on the back face of the chip,the chip can be directly subjected to thermocompression bonding with anAg coat, Au coat or solder coat on the conductive path 51A, or the chipcan be fixed via the brazing material such as solder. Herein, suchconductive coat may be formed on the uppermost layer of the conductivecoats laminated. For example, on the conductive path 51A of Cu, twolayers of Ni coat and Au coat may be applied in due order, three layersof Ni coat, Cu coat and solder coat applied in due order, or two layersof Ag coat and Ni coat applied in due order. Note that a number of otherkinds of conductive coat or lamination structures are considered, butomitted here.

[0142] This circuit device has the insulating resin 50 which is asealing resin to support the conductive paths 51. Therefore, the circuitdevice has no need of the support substrate, and is constituted of theconductive paths 51, the circuit elements 52 and the insulating resin50. This constitution is a feature of the present invention. Asdescribed previously in the paragraph of Related Art, the conductivepaths of the conventional circuit device are supported by the supportsubstrate, or the lead frame, which is not required in the intrinsicconstitution. However, this circuit device is composed of as manyconstitutional elements as needed, without the need of the supportsubstrate. As a result, this circuit device becomes a thin structurewith the inexpensive cost.

[0143] In addition to the constitution as described previously, thiscircuit device has the insulating resin 50 for covering the conductivepath 51 and filled into the trench 54 between the conductive paths 51 tosupport them integrally.

[0144] The interval between these conductive paths 51 with the curvedstructure 59 is the trench 54 where the insulating resin 50 is filled,and has the merit of effecting insulation between the conductive paths51, while preventing the conductive paths 51 from slipping from theinsulating resin 50.

[0145] This circuit device has the insulating resin 50 for covering thecircuit elements 52 to be filled into the trench 54 between theconductive paths 51, and supporting the conductive paths integrally withthe back face of the conductive paths 51 exposed.

[0146] A point of exposing the back face of the conductive paths ischaracteristic of the present invention. The back face of the conductivepaths can be connected with the external. Hence, there is a feature thatthe conventional through hole TH of FIG. 25 can be dispensed with.

[0147] In the case where the circuit elements are directly fixed via theconductive coat made of brazing material, Au, or Ag, the heat developedby the conductive element 52A can be transferred to the mountingsubstrate via the conductive path 51A because the back face of theconductive paths 51 is exposed. Particularly by heat release, thiscircuit device is effective for the semiconductor chips which canimprove the characteristics such as increased drive current.

[0148] This circuit device has a substantially common surface for thetrench 54 and the conductive paths 51. This structure of common surfaceis a feature of the present invention in that the circuit device 53 canbe moved horizontally because there is no step between the backelectrodes 10, 11 as shown in FIG. 25.

[0149] In FIG. 1, a plurality of circuit elements constitute an ICcircuit, and the conductive paths for connection between the circuitelements are wired, with a land configuration as shown in FIG. 1B.However, the practical configuration is more complex as shown in FIGS. 2and 28.

[0150] Further as an another arrangement of the first embodiment, asshown in FIG. 1C, the interval between these conductive paths 51 with astraight structure 59S can be a trench 54s where the insulating resin 50is filled, and has the merit of effecting insulation between theconductive paths 51 as the device such as the first embodiment. Anadvantage of preventing the conductive paths 51 from slipping from theinsulating resin 50 in the arrangement of the embodiment is slightlysmaller than that of the first embodiment.

[0151] Second Embodiment for Circuit Device

[0152] A circuit device 53 of FIG. 2 will be described below.

[0153] This circuit device has substantially the same structure as thatof FIG. 1, except that the interconnects L1 and L2 are formed as theconductive paths 51. Accordingly, the interconnects L1 and L2 will bedescribed below.

[0154] As described before, there are a wide variety of IC circuits froma small-scale circuit to a large-scale circuit. For the convenience ofthe drawings, the small-scale circuit is only shown in FIG. 2A. Thiscircuit is most applicable to an audio amplifying circuit having adifference amplifying circuit and a current mirror circuit connected.The difference amplifying circuit is constituted of a TR1 and a TR2, andthe current mirror circuit is constituted of a TR3 and a TR4, as shownin FIG. 2A.

[0155]FIG. 2B is a plan view of the circuit device to which the circuitof FIG. 2A is applied. FIG. 2C is a cross-sectional view taken along theline A-A in FIG. 2B. FIG. 2D is a cross-sectional view taken along theline B-B. To the left of FIG. 2B, a die pad 51A for mounting the TR1 andTR3 is provided. To the right of FIG. 2B, a die pad 51D for mounting theTR2 and TR4 is provided. On the upper side of the die pads 51A, 51D,there are provided the electrodes for external connection 51B, 51E to51G, and on the lower side thereof, there are provided the electrodesfor external connection 51C, 51H to 51J. Since a TR1 emitter and a TR2emitter are commonly connected, an interconnect L2 is formed integrallywith the electrodes 51E, 51G. Also, since a TR3 base and a TR4 base, aswell as a TR3 emitter and a TR4 emitter are commonly connected, aninterconnect L1 is formed integrally with the electrodes 51C, 55J, andan interconnect L3 is formed integrally with the electrodes 55H, 55I.

[0156] The present invention has a feature of the interconnects L1 toL3. They correspond to the interconnects 25 and 29 in FIG. 28. Theseinterconnects are different depending on the degree of integration ofthis circuit device, and have the width as narrow as 25 μm or more. Notethat this width of 25 μm is a numerical value taken when the wet etchingis used. If the dry etching is used, its width can be narrower.

[0157] As will be clear from FIG. 2D, a conductive path L1 constitutingthe interconnect L1 simply has the back face exposed, and has a lateralface of curved structure which is supported by the insulating resin 50.In other words, the interconnect is buried into the insulating resin 50.Hence, the wires can be prevented from slipping or warping, unlike thewires simply pasted on the support substrate as shown in FIG. 25.Particularly, since the lateral face of the first conductive path is arough face with curved structure, and the visor is formed on the surfaceof the conductive path, there occurs an anchor effect to prevent theconductive path from slipping off the insulating resin, as will beunderstood from a manufacturing method hereinafter described.

[0158] The electrodes 51B, 51C, 551E to 51J for external connection areburied into the insulating resin, as described previously. Therefore,even if an external force is applied via an external lead securedtherein, the electrodes are unlikely to be peeled.

[0159] Third Embodiment for Circuit Device

[0160] A circuit device 56 of FIG. 8 will be described below.

[0161] This circuit device has substantially the same structure of FIG.1 or 2, except that a conductive coat 57 is formed on the surface of theconductive paths 51. Herein, the conductive coat 57 on the conductivepaths will be mainly described below.

[0162] A first feature is to provide the conductive coat 57 to preventthe circuit device or the conductive path 51 from warping.

[0163] Typically, due to a difference in thermal expansion coefficientbetween the insulating resin and the conductive path material(hereinafter referred to as a first material) the circuit device itselfmay be warped, or the conductive path curved or peeled. Since thethermal conductivity of the conductive paths 51 is superior to that ofthe insulating resin, the conductive paths 51 will rise in temperaturemore rapidly, and expand. A second material having a smaller thermalexpansion coefficient than the first material is coated. Thereby, it ispossible to prevent the curvature or exfoliation of the conductivepaths, and the warpage of the circuit device. Particularly, when thefirst material is Cu, the second material is preferably Au, Ni or Pt. Cuhas an expansion coefficient of Cu is 16.7×10−6 (10 to the minus 6thpower), Au 14×10−6, Ni 12.8×10−6, and Pt 8.9×10−6. In this case, aplurality of layers may be formed.

[0164] A second feature is to provide an anchor effect based on thesecond material. A visor 58, which is formed of the second material, isformed over the conductive path 51 to be buried into the insulatingresin 50, bringing about the anchor effect to prevent the slippage ofthe conductive paths 51. The visor 58 can be formed by the conductivepath itself.

[0165] In the present invention, both the curved structure 59 and thevisor 58 develops the double anchor effect to suppress the slippage ofthe conductive paths 51.

[0166] In the above three embodiments, there has been described thecircuit device having a transistor chip 52A and a passive element 52Bmounted. However, the present invention is also applicable to a circuitdevice which is constituted of one semiconductor device sealed therein,as shown in FIGS. 21 and 22. FIG. 21 shows a circuit device 81 in whicha face down element 80 such as a CSP is mounted. FIG. 22 shows a circuitdevice 83 in which the passive element 82 such as a chip resistor orchip capacitor is sealed. Further, the bonding wire may be providedbetween two conductive paths and sealed therein. This is usable as afuse.

[0167] First Embodiment for a Manufacturing Method of a Circuit Device

[0168] Referring to FIGS. 3 to 7 and FIG. 1, a manufacturing method of acircuit device 53 will be described below.

[0169] Firstly, a sheet conductive foil 60 is prepared. This conductivefoil 60 is composed of a material which is selected in consideration ofthe adhesive property to the brazing material, bonding property andplating property. Specifically, the material may be Cu or Al as the mainconstituent, or an alloy of Fe—Ni. Further lamination plate of Cu and Alis applicable. The conductive foil is preferably about 10 μm to 300 μmthick in view of the etching that is performed later. Herein, a copperfoil having a thickness of 70 μm (2 ounces) is used. However, thethickness may be fundamentally over 300 μm or less than 10 μm. It issufficient that the trench 61 which has a smaller depth than thethickness of the conductive foil 60 may be formed, as will be describedlater.

[0170] The sheet laminated conductive foil 60 is rolled in a desiredwidth, and may be carried to each process as will be described later, ormay be cut in a predetermined size, the cut conductive foils beingcarried to each process.

[0171] Subsequently, there are a step of removing the conductive foil60, except for at least a region which becomes the conductive paths 51,below a thickness of the conductive foil 60, a step of mounting thecircuit elements 52 on the conductive paths 60, and a step of coatingthe insulating resin 50 in the trench 61 formed at the step of removingand the conductive foil 60 to seal the circuit elements.

[0172] Firstly, a photo-resist (PR) (etching resistant mask) is appliedon the conductive foil 60 of Cu, and patterned to expose the conductivefoil 60 excluding the region which becomes the conductive paths 51, asshown in FIG. 4. And etching is performed via the photo-resist PR, asshown in FIG. 5A.

[0173] This manufacturing method has a feature that the wet etching ordry etching can be performed non-anisotropically by selecting theetching condition. Then the lateral face (side surface) is a rough faceand curved. Note that the depth of the trench 61 formed by etching isabout 50-70 μm.

[0174] In the wet etching, etchant may be ferric chloride or cupricchloride. The conductive foil may be dipped in this etchant, or thisetchant may be showered.

[0175] Particularly as shown in FIG. 5B, etching in the transversaldirection is difficult to proceed directly under the photo-resist PR asthe etching mask, but is gradually made in a deeper portion of thetrench 61 in the transversal direction. As shown in the figure, withreference to a certain position on the lateral face of the trench 61,the size of aperture corresponding to its position is smaller withincreased height, to taper inversely, resulting in the anchor structure.By showering, the etching proceeds in the depth direction, but issuppressed in the transversal direction, so that this anchor structurebecomes remarkable.

[0176] In the dry etching, the orientation-dependent (anisotoropic)etching or non-anisotropic etching can be made. At present, it is saidthat Cu can not be removed by reactive ion etching. Cu can be removed bysputtering. The orientation-dependent etching or non-anisotropic etchingcan be effected, depending on the sputtering or etching conditions.

[0177] In FIG. 5, a conductive material which is resistant to theetching liquid may be selectively coated, instead of the photo-resist.By coating selectively this conductive material on a portion serving asthe conductive path, this conductive material becomes an etchingprotective film, so that the trench can be etched without the use of thephoto resist PR. The conductive materials may include Ag, Au, Pt, Pd orN. These corrosion resistant conductive materials have a feature ofbeing readily available as the die pad or bonding pad.

[0178] For example, Ag can be bonded with Au and the brazing material.Hence, if Au has been coated on the back face of chip, thethermocompression bonding of chip can be effected with the Ag on theconductive coat 51, or the chip can be fixed via the brazing materialsuch as solder. Since the Au bonding wire can be bonded to theconductive coat of Ag, the wire bonding is allowed. Accordingly, thereis provided a merit that these conductive coats can be directly utilizedas the die pad and the bonding pad.

[0179] Subsequently, there is a step of connecting electrically thecircuit elements 52 to the conductive foil 60 formed with the trench 61,as shown in FIG. 6.

[0180] The circuit elements 52 include the semiconductor device 52A suchas a transistor, a diode and an IC chip, and the passive element 52Bsuch as a chip capacitor and a chip resistor. Though being thick, a facedown semiconductor device such as CSP or BGA can be mounted.

[0181] Herein, the bare transistor chip 52A is die bonded to theconductive path 51A. Also, the emitter electrode and the conductive path51B, as well the base electrode and the conductive path 51B, areconnected via the bonding wire 55A which has been fixed by ball bondingwith thermocompression, or wedge bonding with ultrasonic wave. The chipcapacitor or the passive element 52B is fixed via the brazing materialsuch as solder or the conductive paste 55B.

[0182] When the pattern of FIG. 28 is applied in this embodiment, thebonding pad 26, which is very small in size, is provided integrally withthe conductive foil 60, as shown in FIG. 5. Hence, there is a merit thatthe energy of bonding tool can be transferred, with greater bondingability. In cutting the bonding wire after bonding, the bonding wire maybe pull-cut. Then, since the bonding pad is integrated with theconductive foil 60, floating of the bonding pad can be suppressed,leading to better pull-cut ability.

[0183] Further, there is a step of attaching the insulating resin 50onto the conductive foil 60 and the curved trench 61, as shown in FIG.7. This can be performed by transfer molding, injection molding, dippingor application. The resin materials include a thermosetting resin suchas epoxy resin for which the transfer molding is suitable, and athermoplastic resin such as polyimide resin and polyphenylene sulfidefor which the injection molding is usable.

[0184] In this embodiment, the insulating resin applied on the surfaceof the conductive foil 60 is adjusted so as to cover the thickness ofabout 100 μm from the top of the bonding wire 55A. This thickness may beincreased or decreased in consideration of the strength of the circuitdevice.

[0185] A feature of this step is that the conductive foil 60, whichbecomes the conductive paths, serves as the support substrate up tobeing coated with the insulating resin 50. Conventionally, the supportsubstrate 5 which is intrinsically not required is adopted to form theconductive paths 7 to 11, as shown in FIG. 26. In the present invention,the conductive foil 60 which becomes the support substrate is anecessary substance for the electrodes. Therefore, there is a merit thatthe operation can be effected by saving the material, with less cost.

[0186] The trench 61 has a smaller depth than the thickness of theconductive foil. Therefore, the conductive foil is not separatedindividually into the conductive paths. Accordingly, it can be treatedintegrally as one sheet conductive foil 60. It has a feature of the easyoperation of carrying or mounting it onto the mold, when molding theinsulating resin.

[0187] Further, since the insulating resin 50 is fitted into the trench61 having the curved structure, there occurs the anchor effect in thisregion to prevent the insulating resin 50 from being peeled, and theconductive paths 51 from slipping off the insulating resin 50, theconductive paths 51 being separated at the later step.

[0188] Before coating this insulating resin 50, the silicone resin maybe potted to protect the semiconductor chip or the connecting part ofbonding wire, for example.

[0189] Subsequently, there is a step of removing chemically and/orphysically the back face of the conductive foil 60 for separation intothe conductive paths 51. This step of removing can be effected bypolishing, grinding, etching, or metal evaporation using a laserirradiation.

[0190] In the experiments, the circuit device was cut about 30 μm thickover the entire surface by a polishing or grinding apparatus to exposethe insulating resin 50 from the trench 61. This exposed face isindicated by the dot line in FIG. 7. As a result, each of the conductivepaths 51 is about 40 μm thick. Before the insulating resin 50 isexposed, the conductive foil may be subjected to wet etching over theentire surface thereof. Then, the conductive foil may be cut over theentire surface by the polishing or grinding apparatus to expose theinsulating resin 50. Further conductive path 51 can be separated by onlywet etching step.

[0191] As a result, the conductive paths 51 are exposed from theinsulating resin 50. And the trench 61 is cut, resulting in the trench54 as shown in FIG. 1 (see FIG. 7).

[0192] Lastly, a conductive material such as solder 5D may be appliedonto the second conductive paths 51 exposed, as required, to completethe circuit device as shown in FIG. 1.

[0193] In the case where the conductive material is coated on the backface of the conductive paths 51, the conductive coat may be formed aheadon the back face of the conductive foil of FIG. 3. In this case, theconductive coat may be selectively applied on the portion correspondingto the conductive path. The way of coating may be by plating. Thisconductive coat may be a material resistant to etching. When thisconductive coat is adopted, the conductive paths 51 can be formed onlyby etching, without polishing.

[0194] With this manufacturing method, the transistor and the chipresistor are only mounted on the conductive foil 60, but may be arrangedin a matrix of transistors and chip resistors, or a matrix of circuitsas shown in FIG. 28. In this case, the matrix can be divided intoindividual units by using a dicing apparatus, as will be describedlater.

[0195] With this manufacturing method, the circuit device 56 of flattype can be fabricated in which the conductive paths 51 are buried intothe insulating resin 50, and there is a common back face for theconductive paths 51 and the insulating resin 50.

[0196] A feature of this manufacturing method is that the insulatingresin 50 is utilized as the support substrate and can be separated intothe individual conductive paths.

[0197] The insulating resin 50 is required to have the conductive paths51 buried therein. There is no need of having unnecessary supportsubstrate 5, unlike the conventional manufacturing method of FIG. 26.Accordingly, it can be manufactured with the minimum amount of material,with less cost.

[0198] The thickness of the insulating resin from the surface of theconductive paths 51 can be adjusted when the insulating resin isattached at the previous step. Accordingly, the thickness of the circuitdevice 56 can be increased or decreased, depending on the circuitelement to be mounted. Herein, in the circuit device, the conductivepaths 51 having a thickness of 40 μm is buried into the insulating resin50 having a thickness of 400 μm (see FIG. 1).

[0199] Second Embodiment for a Manufacturing Method of a Circuit Device

[0200] Referring to FIGS. 9 to 13 and FIG. 8, a manufacturing method ofa circuit device 56 having a visor 58 will be described below. Thesecond embodiment is substantially the same as the first embodiment(FIGS. 1 and 2), except that a second material 70 which serves as thevisor is applied. The details are not described here.

[0201] Firstly, a laminated conductive foil 60 is prepared in which thesecond material 70 having a small etching rate is applied on theconductive foil 60 made of the first material, as shown in FIG. 9.

[0202] For example, if Ni is applied on the Cu foil, Cu and Ni can beetched by ferric chloride or cupric chloride at a time, advantageouslyresulting in the formation of the visor 58 of Ni, due to a differencebetween etching rates. The bold line indicates the conductive coat 70made of Ni, its film thickness being preferably about 1 to 10 μm. Thelarger film thickness of Ni can form the visor 58 more easily.

[0203] The second material may cover the first material as well as thematerial for selective etching. In this case, the film made of thesecond material is firstly patterned to cover the formed area of theconductive paths 51. Then, with this film as a mask, the first materialis etched so that the visor 58 can be formed. The second materials mayinclude Al, Ag, Pd and Au (see FIG. 9).

[0204] Subsequently, there is a step of removing the conductive foil 60except for at least the region which becomes the conductive paths 51below the thickness of the conductive foil 60.

[0205] The photo-resist PR is formed on the Ni conductive coat 70, andpatterned so that the Ni conductive coat 70 may be exposed except forthe region which becomes the conductive paths 51, as shown in FIG. 10.Then, etching is performed with the photo-resist, as shown in FIG. 11.

[0206] As described previously, if etching is performed, using anetchant such as ferric chloride or cupric chloride, the visor 58 jutsout as the etching proceeds, because the Ni conductive coat 70 has aslower etching rate than the conductive foil Cu 60.

[0207] The steps of mounting the circuit elements 52 on the conductivefoil 60 with the trench 61 formed (FIG. 12), covering the insulatingresin 50 over the conductive foil 60 and the trench 61, removing theback face of the conductive foil 60 chemically and/or physically forseparation into the conductive paths 51 (FIG. 13), and forming theconductive coat on the back face of the conductive paths to complete thecircuit device (FIG. 8) are the same as those of the previousmanufacturing method, and not described again.

[0208] Third Embodiment for a Manufacturing Method of a Circuit Device

[0209] Referring to FIGS. 14 to 20, a method for manufacturing a circuitdevice will be described below, in which the IC circuits having theconductive paths composed of a plurality of kinds of circuit elements,wires, die pads and bonding pads are arranged like a matrix and dividedinto individual IC circuits after sealing. Referring to FIG. 2 andparticularly a cross-sectional view of FIG. 2C, the structure will bedescribed below. This manufacturing method is substantially the same asin the first embodiment and the second embodiment, and is simplydescribed.

[0210] Firstly, a sheet conductive foil 60 is prepared, as shown in FIG.14.

[0211] The sheet conductive foil 60 is rolled in a predetermined width,and may be carried to the later process. Or the conductive foils cut ina predetermined size may be prepared and carried to the later process.

[0212] Subsequently, there is a step of removing the conductive foil 60except for at least the region which becomes the conductive paths 51below the thickness of the conductive foil 60.

[0213] Firstly, the photo-resist PR is made on the Cu foil 60, andpatterned so that the conductive foil 60 may be exposed except for theregion which becomes the conductive paths 51, as shown in FIG. 15. Andetching is performed via the photo-resist PR, as shown in FIG. 16.

[0214] The trench 61 formed by etching is 50 μm in depth, for example,with its lateral face being rough, leading to increased adhesiveness ofthe insulating resin 50.

[0215] The lateral face of the trench 61 is etched non-anisotropically,and curved. This step of removing can be wet etching, or dry etching.This curved structure produces the anchor effect. (For more details,refer to the first embodiment for the manufacturing method of thecircuit device.)

[0216] In FIG. 15, a conductive material which is resistant to theetching solution may be selectively coated, instead of the photo-resistPR. If it is selectively coated on the portion for the conductive paths,this conductive material serves as an etching protective film. As aresult, the trench can be etched without the use of resist.

[0217] Subsequently, there is a step of electrically connecting andmounting the circuit elements 52A to the conductive foil 60 formed withthe trench 61, as shown in FIG. 17.

[0218] The circuit elements 52A include semiconductor devices such as atransistor, a diode, and an IC chip, and passive elements such as a chipcapacitor and a chip resistor. Also, though being thicker, the face downsemiconductor devices such as CSP and BGA may be mounted.

[0219] Herein, the bare transistor chip 52A is die bonded to theconductive path 51A. Consequently, the emitter electrode and theconductive path 51B, as well as the base electrode and the conductivepath 51B are connected via the bonding wire 55A.

[0220] Furthermore, there is a step of applying the insulating resin 50to the conductive foil 60 and the trench 61, as shown in FIG. 18. Thisstep can be performed by transfer molding, injection mold, or dipping.

[0221] In this embodiment, the insulating resin applied on the surfaceof the conductive foil 60 is adjusted to be about 100 μm thick from thetop of the circuit elements mounted. This thickness can be made thickeror thinner in view of the strength of the circuit device.

[0222] A feature of this step is that the conductive foil 60, whichbecomes the conductive paths 51, serves as the support substrate, whencoated with the insulating resin 50. Conventionally, the supportsubstrate 5 which is intrinsically not required is used to form theconductive paths 7 to 11, as shown in FIG. 26. In the present invention,the conductive foil 60 which becomes the support substrate is anecessary substance for the electrodes. As a result, the manufacturingoperation can be performed by saving the material, with less cost.

[0223] The trench 61 has a smaller depth than the thickness of theconductive foil. Therefore, the conductive foil is not separatedindividually into the conductive paths 51. Accordingly, it can betreated integrally as one sheet conductive foil 60. It has a feature ofthe easy operation of carrying or mounting it onto the mold, whenmolding the insulating resin.

[0224] Subsequently, there is a step of removing chemically and/orphysically the back face of the conductive foil 60 for separation intothe conductive paths 51. This step of removing can be effected bypolishing, grinding, etching, or metal evaporation with laser.

[0225] In the experiments, the circuit device was cut about 30 μm thickover the entire surface by a polishing or grinding apparatus to exposethe insulating resin 50. This exposed face is indicated by the dot linein FIG. 18. As a result, each of the conductive paths 51 is about 40 μmthick. Before the insulating resin 50 is exposed, the conductive foil 60may be subjected to wet etching over the entire surface thereof. Then,the conductive foil may be cut over the entire surface by the polishingor grinding apparatus to expose the insulating resin 50.

[0226] As a result, the surface of the conductive paths 51 is exposedfrom the insulating resin 50.

[0227] Further, a conductive material such as solder is applied on theexposed conductive paths 51, as shown in FIG. 19.

[0228] Lastly, there is a step of completing the circuit device byseparation into individual circuit elements, as shown in FIG. 20.

[0229] The separation line is indicated by the arrow, and separation canbe effected by dicing, cut, press, or chocolate break. When using thechocolate break, a projection on the mold may be provided to form thegroove at the separation line in coating the insulating resin.

[0230] Particularly, the dicing is mostly used in the manufacturingmethod of the semiconductor devices, and is preferable because it cancut very small things.

[0231] The manufacturing method as described in the first to thirdembodiments allows for the complex patterns, as shown in FIG. 28.Particularly, the wire is bent and integral with the bonding pad 26, theother end being electrically connected with the circuit element. Thewire is narrow in width, and long. Therefore, the warp (curvature)caused by heat is very significant, resulting in exfoliation in theconventional structure. However, in the present invention, since thewires are buried into the insulating resin and supported, it is possibleto prevent curvature, exfoliation and slippage of the wires. The bondingpad itself has a small plane area, and may be peeled in the conventionalstructure. However, since in the present invention, the bonding pad isburied into the insulating resin and supported by the insulating resin,with the anchor effect, there is a merit of preventing the slippage.

[0232] Further, there is another merit that the circuit device havingthe circuit elements buried into the insulating resin 50 can beproduced. This is similar to the conventional structure in which thecircuit is incorporated into a printed circuit board or a ceramicsubstrate. This will be described later in connection with a way ofmounting.

[0233] To the right of FIG. 27, a simple flow diagram of the presentinvention is presented. The circuit device can be fabricated inaccordance with the nine steps of preparing a Cu foil, plating with Agor Ni, half etching, die bonding, wire bonding, transfer molding,removing the back face of Cu foil, treating the back face of conductivepath, and dicing (dividing to a plurality of devices). And all the stepscan be performed in the inside work without supplying the supportsubstrate from the manufacturer.

[0234] Mode for Providing Various Kinds of Circuit Devices and the Waysof Mounting

[0235]FIG. 21 shows a circuit device 81 having a face down circuitelement 80 mounted. The circuit element 80 is a bare semiconductor chipwhich have solder ball in the face, CSP or BGA having sealed surface.FIG. 22 shows a circuit device 83 having a passive element 82 such as achip resistor mounted. They are of thin type because of no need of thesupport substrate. Also, they are sealed by the insulating resin, andsuperior in the environmental resistance.

[0236]FIG. 23 shows the mounting structure. Firstly, FIG. 23A shows thecircuit devices 53, 81, and 83 as described above, which are mounted inthe conductive paths 85 formed on a mounting substrate 84 such as aprinted circuit board, metal substrate, or ceramic substrate.

[0237] Particularly, a conductive path 51A to which the back face of asemiconductor chip 52 is fixed is thermally coupled to the conductivepaths 85 on the mounting substrate 84. Therefore, the heat of thecircuit device can be radiated via the conductive paths 85. If the metalsubstrate is used for the mounting substrate 84, the temperature of thesemiconductor chip 52 can be further decreased, due to radiation of themetal substrate. Therefore, the driving capability of the semiconductorchip can be enhanced.

[0238] For example, the power MOS, IGBT, SIT, large current drivingtransistors, and large current driving IC (MOS, BIP, Bi-CMOS), memory ICare preferable.

[0239] The metal substrates preferably include an Al substrate, a Cusubstrate and a Fe substrate. In view of the short-circuit with theconductive paths 85, the insulating resin and/or oxide films are formed.

[0240]FIG. 23B shows a circuit device 90 of the invention which isutilized as the substrate 84 of FIG. 23A. This is the greatest featureof the present invention. Namely, the conventional printed circuit boardor ceramic substrate has a through hole TH formed in the substrate. Inthe present invention, a substrate module containing an IC circuit canbe fabricated. For example, at least one circuit (which may be containedas the system) is contained in the printed circuit board.

[0241] Conventionally, the support substrate used the printed circuitboard or ceramic substrate. In the present invention, the substratemodule does not need the support substrate. This substrate module can bethinner and lighter than a hybrid substrate which may be the printedcircuit board, the ceramic substrate, or the metal substrate.

[0242] This circuit device 90 is utilized as the support substrate, andthe circuit elements can be mounted in the exposed conductive paths,resulting in a high performance substrate module. Particularly, if thiscircuit device is a support substrate and a circuit device 91 is mountedon the support substrate, the substrate module can be made furtherthinner and lighter.

[0243] Accordingly, according to the above embodiments, an electronicapparatus with this module mounted can be reduced in size and weight.

[0244] The hatching part indicated by numeral 93 is an insulating film.For example, a high molecular film such as solder resist is preferable.Due to formation of this film, it is possible to prevent the conductivepaths buried into the substrate 90 and the electrodes formed on thecircuit elements 91 from short-circuiting.

[0245] Referring to FIG. 29, there will be described some merits of thepresent circuit device in the following. In the conventional mountingmethod, the semiconductor manufacturers fabricated the package typesemiconductor devices and flip chips. The set makers mounted thesemiconductor devices supplied from the semiconductor manufacturers andthe passive elements supplied from the parts makers on the printedcircuit board and incorporated the circuit devices into the set tofabricate an electronic apparatus. However, since the circuit device ofthis invention allows itself to be used as the mounting substrate, thesemiconductor manufacturers can complete the mounting substrate modulein the later process, and deliver it to the set makers. Accordingly, theset makers can greatly save the operation of mounting the elements onthe substrate.

[0246] As will be clearly understood, the present invention canfabricate the circuit devices with the conductive paths and the minimumamount of insulating resin, resulting in less wasteful resources. Hence,the circuit devices can be fabricated with less superfluous componentsup to completion, and with greatly reduced cost. The film thickness ofinsulating resin, and the thickness of conductive foil, can beoptimized, to make the circuit device smaller, thinner and lighter.Furthermore, since the wires liable to curvature or exfoliation areburied into the insulating resin, those problems can be resolved.

[0247] Since the back face of conductive paths is exposed from theinsulating resin, the back face of conductive paths can be directlycontacted with the external. Hence, there is an advantage that the backface electrode and through hole of the conventional structure can bedispensed with.

[0248] When the circuit elements are directly fixed via the conductivecoat made of the brazing material, Au or Ag, the heat developed by thecircuit elements can be transferred directly via the conductive paths tothe mounting substrate, because the back face of conductive paths isexposed. Particularly, the power elements can be also mounted, due tothis heat radiation.

[0249] This circuit device has a flat plane structure in which thesurface for the trench is substantially coincident with the surface forthe conductive paths. If a narrow pitch QFP is mounted on the supportsubstrate, the circuit device itself can be moved horizontally, as shownin FIG. 23B. Consequently, the lead shift can be easily modified.

[0250] Since the second material is formed on the surface of theconductive paths, the warping of the mounting substrate, or particularlythe curvature or exfoliation of the fine slender wire can be prevented.

[0251] Since the conductive paths has the curved structure on thelateral face, and/or the second material is formed on the surface ofconductive paths, a visor applied to a conductive path can be formed,bringing about the anchor effect to prevent the conductive paths fromwarping and slipping.

[0252] In the manufacturing method of the circuit device according tothe present invention, the conductive foil itself serving as theconductive paths is utilized as the support substrate. The wholesubstrate is supported by the conductive foil, up to the steps offorming the trench or mounting the circuit elements and applying theinsulating resin, while to divide the conductive foil into theconductive paths, the insulating resin is used as the support substrate.Accordingly, the circuit device of the invention can be manufacturedwith the least amount of circuit elements, conductive foil, andinsulating resin, as required. As described in the conventional example,this circuit device can be fabricated without need of having the supportsubstrate and with the reduced cost. Since the support substrate isunnecessary, the conductive paths are buried into the insulating resin,with the adjustable thickness of the insulating resin and the conductivefoil, there is a merit that the circuit device can be made very thin. Informing the trench, the curved structure results, bringing about theanchor effect.

[0253] As will be apparent from FIG. 27, the steps of forming thethrough hole and printing the conductors (for the ceramic substrate) canbe omitted. Therefore, the manufacturing process can be significantlyshortened, and advantageously the whole process can be performed in theinside work. Also, the frame mold is unnecessary at all, leading toquite short delivery.

[0254] Since the conductive paths can be treated integrally, up to thestep of removing the conductive foil (e.g., half etching), there is anadvantage of the enhanced workability in the later step of coating theinsulating resin.

[0255] Since there is a common face for the conductive paths and theinsulating resin, the circuit device mounted can be moved without impactupon the lateral face of the conductive paths on the mounting substrate.Particularly, the circuit device mismounted can be redisposed byshifting it horizontally. If the brazing material is molten aftermouting the circuit device, the circuit device mismounted will tend toget back onto the conductive path, owing to surface tension of themolten brazing material. Consequently, the reallocation of circuitdevice can be effected by itself.

[0256] Lastly, this circuit device can be utilized as the supportsubstrate to mount the circuit elements in the exposed conductive paths,resulting in a substrate module with high performance. Particularly, ifthis circuit device is used as the support substrate and the circuitdevice 91 as the circuit element is mounted thereon, the substratemodule can be made lighter and thinner.

What is claimed is:
 1. A circuit device, comprising: a plurality ofconductive paths; a circuit element mounted on said desired conductivepaths; and a package of an insulating resin for coating said circuitelement and supporting integrally said conductive paths; a plurality oflead terminals for connecting with outer circuit, the lead terminalsbeing exposed from one surface of the package
 2. A circuit deviceaccording to claim 1, wherein said conductive paths are made of pressedmetal.
 3. A circuit device according to claim 1, wherein at least one ofthe plurality of said conductive paths as a curved lateral face to befitted with said insulating resin.
 4. A circuit device according toclaim 3, wherein said conductive paths are formed by etching step.
 5. Acircuit device according to claim 1, wherein said circuit devicecomprises a plurality of circuit elements fixed on said desiredconductive paths; and at least one of the plurality of said conductivepaths is used for an interconnect to electrically connect the pluralityof said circuit elements.
 6. A circuit device according to claim 1,wherein said conductive paths have a thickness within a range between20-100 μm.
 7. A circuit device according to claim 1, wherein saidconductive paths made of pressed metal comprising mainly cooper.
 8. Acircuit device according to claim 1, wherein said conductive paths madeof pressed metal comprising mainly iron-nickel.
 9. A circuit deviceaccording to claim 1, wherein said conductive paths made of pressedmetal comprising mainly aluminum.
 10. A circuit device according toclaim 1, wherein said conductive paths are formed so that a surface ofthe conductive paths is flat and the particle boundaries are disposed atrandom.
 11. A circuit device according to claim 1, wherein a conductivecoat which is made of a metallic material different from that of saidconductive paths is provided on a surface of said conductive paths, onwhich the circuit element is mounted.
 12. A circuit device according toclaim 11, wherein said conductive coat is made of nickel plated.
 13. Acircuit device according to claim 11, wherein said conductive coat ismade of gold plated.
 14. A circuit device according to claim 11, whereinsaid conductive coat is made of silver plated.
 15. A circuit deviceaccording to claim 1, wherein said circuit element is constituted ofsemiconductor integrated circuit chip.
 16. A circuit device according toclaim 1, wherein said circuit element is constituted of semiconductorchip circuit part.
 17. A circuit device according to claim 1, wherein aninterconnect between said circuit element and said conductive paths isperformed by a bonding wire.
 18. A circuit device according to claim 1,wherein an interconnect between said circuit element and said conductivepaths is performed by direct bonding.
 19. A circuit device according toclaim 1, wherein the back face of said conductive paths and the backface of said insulating resin filled into said trench are substantiallysame face.
 20. A circuit device according to claim 1, wherein the backface of said conductive paths protrudes from the back face of saidinsulating resin filled into said trench.
 21. A circuit device accordingto claim 1, wherein the back face of said insulating resin filled intosaid trench protrudes from the back face of said conductive paths, andsolder balls for contacting with outer circuit are formed on the backface of said conductive paths.
 22. A method of manufacturing a circuitdevice comprising the steps of: preparing a conductive plate, formingpatterns for forming a conductive paths by forming a trench forisolation having a smaller depth than the thickness of said conductiveplate on said conductive plate excluding at least a region which becomesa conductive path; mounting a circuit element on a surface of saiddesired conductive paths, on the surface of which the trench is formed;molding said circuit elements with an insulating resin to be filled intosaid trench for fitting said conductive paths with said insulatingresin; and forming a circuit by removing said conductive plate from anopposite surface side against the surface for mounting a circuit elementto a depth reaches to the trench, to enable an interconnect formed of apart of said conductive path to be electrically connected with saidplurality of circuit elements.
 23. A method for manufacturing a circuitdevice according to claim 22, comprising the steps of: preparing apressed metal as the conductive plate, and forming a corrosion resistantconductive coat on at least a region which becomes a conductive path onthe surface of said pressed metal; forming the conductive paths byforming a trench having a smaller depth than the thickness of saidpressed metal on said pressed metal excluding at least a region whichbecomes a conductive path; mounting a plurality of circuit elements onsaid desired conductive paths; providing connecting means forelectrically connecting an electrode of said circuit element withdesired one of said conductive path; molding said circuit elements withan insulating resin to be filled into said trench for fitting saidconductive paths with said insulating resin; and forming a circuit byremoving said pressed metal to a depth reached to the trench, to enablean interconnect formed of a part of said conductive path to beelectrically connected with said plurality of circuit elements.
 24. Amethod for manufacturing a circuit device according to claim 22, whereinthe step of preparing a conductive plate comprises a step of preparingcomprises a step of pressing a metal.
 25. A method for manufacturing acircuit device according to claim 22, wherein said step of formingpatterns comprises a step of forming a conductive paths so as to have acurved lateral surface.
 26. A method for manufacturing a circuit deviceaccording to claim 22, wherein said step of forming patterns comprises astep of forming an isolation trench by half etching step.
 27. A methodfor manufacturing a circuit device according to claim 22, wherein saidstep of forming patterns comprises a step of forming an isolation trenchby half pressing step.
 28. A method for manufacturing a circuit deviceaccording to claim 22, wherein said step of mounting comprising aplurality of circuit elements.
 29. A method for manufacturing a circuitdevice according to claim 22, wherein said step of forming a trench ofconductive paths comprises a step of forming the trench so as to have athickness within a range between 20-100 μm.
 30. A method formanufacturing a circuit device according to claim 22, wherein said stepof forming a pattern of conductive paths comprises a step of forming thepattern made of pressed metal comprising mainly cooper, by hot pressmethod.
 31. A method for manufacturing a circuit device according toclaim 22, wherein said step of forming a pattern of conductive pathscomprises a step of forming the pattern made of pressed metal comprisingmainly silver, by hot press method.
 32. A method for manufacturing acircuit device according to claim 22, wherein said step of forming apattern of conductive paths comprises a step of forming the pattern madeof pressed metal comprising mainly aluminum, by hot press method.
 33. Amethod for manufacturing a circuit device according to claim 22, saidstep of preparing a conductive plate comprises step of forming aconductive plate so that the surface of the conductive paths is flat andthe particle boundaries are disposed at random.
 34. A method formanufacturing a circuit device according to claim 22, said step ofpreparing a conductive plate comprises step of forming a conductive coatwhich is made of a metallic material different from that of saidconductive paths is provided on a surface of said conductive paths, onwhich the circuit element is mounted.
 35. A method for manufacturing acircuit device according to claim 33, wherein said step of forming aconductive coat comprising a nickel plating step.
 36. A method formanufacturing a circuit device according to claim 33, wherein said stepof forming a conductive coat comprising a gold plating step.
 37. Amethod for manufacturing a circuit device according to claim 33, whereinsaid step of forming a conductive coat comprising a silver plating step.38. A method for manufacturing a circuit device according to claim 22,wherein said step of mounting a circuit element comprises a step ofmounting a semiconductor integrated circuit chip on the conductivepaths.
 39. A method for manufacturing a circuit device according toclaim 22, wherein said step of mounting a circuit element comprises astep of mounting a semiconductor chip circuit part on the conductivepaths.
 40. A method for manufacturing a circuit device according toclaim 22, wherein said step of mounting a circuit element comprises awire bonding step for connecting the circuit element with the conductivepaths.
 41. A method for manufacturing a circuit device according toclaim 22, wherein said step of mounting a circuit element comprises adirect bonding step for connecting the circuit element with theconductive paths.
 42. A circuit device according to claim 22, whereinsaid step of forming a circuit comprises a step of removing the backface of said conductive paths and the back face of said insulating resinfilled into said trench are substantially same face.
 43. A circuitdevice according to claim 22, wherein said step of forming a circuitcomprises a step of removing the back face of said conductive paths sothat removing the back face of said conductive paths protrudes from theback face of said insulating resin filled into said trench.
 44. Acircuit device according to claim 22, wherein said step of forming acircuit comprises a step of removing the back face of said conductivepaths so that removing the back face of insulating resin filled intosaid trench protrudes from the back face of said conductive paths.
 45. Acircuit device according to claim 22, wherein said step of forming acircuit comprises a step of removing the back face of said conductivepaths so that removing the back face of insulating resin filled intosaid trench protrudes from the back face of said conductive paths; andthe step of forming solder balls for contacting with outer circuit onthe back face of said conductive paths.
 46. A circuit device accordingto claim 22, further comprising the step of dicing the insulating resinfor separation into individual circuit devices.